Air guiding trim chute



y 6 G. w. KARR 3,252,366

AIR GUIDING TRIM CHUTE Filed March 23, 1964 2 Sheets-Sheet 1 N \0INVENTOR.

ATTO 1 EYS y 4, 1966 G. w. KARR 3,252,366

AIR GUIDING TRIM CHUTE Filed March 23, 1964 2 Sheets-Sheet 2 l N VENTORUnited States Patent 3,252,366 AIR GUIDING TRIM CHUTE Gerald W. Karr,West Chester, Pa., assignor, by mesne assignments, to Beloit EasternCorporation, Downingtown, Pa., a corporation of Delaware Filed Mar. 23,1964, Ser. No. 353,900 6 Claims. (Cl. 83-98) The present inventionrelates to improvements in web slitters and particularly to a slitterfor trimming a strip from the edge of a travelling web.

Presently used trim slitters generally embody an upper slitter knifewith a lower slitter band and require a deflector coming in from abovethe web to direct the trimmed strip downwardly into duct work to carrythe trimmed strip away. At higher speeds and when beginning the trimmingoperation the trimmed strip tends to bunch up against the deflector andefforts to prevent this, such as providing a highly polished surface onthe deflector, have not proven entirely satisfactory. Efforts to carrythe trimmed strip away by pulling it downwardly faster than the webspeed have required the provision of a support under the trimmed stripat the location where it is being cut to prevent tearing of the webahead of the slitting point, This usually consists of a rotating hub ofthe same outer diameter as the slitting band and the hub is usuallycarried on the shaft of the band. Speed and weight limitations preventusing a hub of not more than approximately two inches in width whichcannot handle trim widths of more than four inches.

Accordingly it is an object of the present invention to provide animproved trim slitter which avoids the disadvantages of the prior" art,and which insures uniform and proficient carrying away of the trimmededge without danger of bunching both at high speeds and at starting.

Another object of the invention is to provide an improved trim slitterwhich avoids the necessity of providing a rotating hub outside of theslitter band and yet does not permit tearing of the web ahead of theslit and which provides advantages over the supporting rotating hubarrangement in that it permits trimming edges of much wider width thanheretofore possible.

A further object of the invention is to provide a means for handling andcarrying away the trimmed edge of a web in a trim slitter which does notencumber the normal operation of the trim slitter and which permitsaxially shifting the upper slitter knife axially outwardly away from theband and maintains the space clear which is required for this shiftingmovement.

A still further object of the invent-ion is to provide a trim slitterwhich is capable of operating at high speeds without tearing the webahead of the slitter and avoids the provision of the supporting hub ordummy band with the air cushion which it creates at high speeds raisingthe edge of the web and avoiding the extra weight which it creates onthe slitter band shaft.

A still further object of the invention is to provide an improved trimslitter which provides for easier threading of the web on start-up,eliminates flutter caused by air film on rotating trim supports,provides cleaner and straighter edges on the slits and improved ends onwound rolls, requires no relocating when the trim width is changed andavoids cumbersome overhead or other unnecessary mounting structure, andreduces the friction surfaces in the path of the trim providing a unitwhich is long wearing and reliable.

A feature of the invention is to provide a web slitter for trimming astrip from the edge of a travelling web including an upper circularslitter knife, a lower slitter band coacting with the knife and a trimstrip chute having a lower plate with a first horizontal surface portionoutwardly of the slitters below the slitter knife to permit its beingaxially shifted outwardly, and having another surface portion curvingdownwardly of the path of the web with air jets in its surface fordirecting a flow of high velocity air into the space between the surfaceand the trimmed strips so that the strip will be controllably held tofollow a cushion of air along the surface.

Other objects, advantages and features will become more apparent withthe teaching of the principles of the present invention in connectionwith the disclosure of the preferred embodiment thereof in thespecification, claims and drawings, in which:

FIGURE 1 is a somewhat schematic side elevational view showing a slittermechanism embodying the principles of the present invention;

FIGURE 2 is a front elevational view of the mechanism of FIGURE 1 withparts broken away for clarity;

FIGURE 3 is an enlarged detailed side elevational view of the trim chuteof the mechanism of FIGURE 1;

FIGURE 4 is a sectional view taken substantially along line IV--IV ofFIGURE 3; and

FIGURE 5 is a top plan view of the chute of FIG- GURE 3.

As shown on the drawings:

FIGURES l and 2 show a travelling web W having an edge T trimmed fromthe Web. For slitting and trimming the edge T from the web W an uppercircular slitter knife 10 is positioned above the web coacting with alower slitter band 11. The trimmed strip T passes down into a chute 12.The trimmed web W continues onwardly over a guide 13 to a winder drum 14to be wound on a roll 14a.

The slitter band 11 is driven by a direct drive motor 16 and the trimchute 12 is mounted on the motor framework including brackets 17. Thusthe trim chute 12 will be positioned in accordance with positioning ofthe slitter band 11.

The slitter knife or blade 10 is provided with mechanism for moving itaxially outwardly independent of the band, the mechanism being shownschematically by the arrowed line 10a, FIGURE 2. The present arrangementprovides a support for the trim strip and is below the lower edge of theslitter blade 10 so that the slitter blade will clear the mechanism asit is moved axially outwardly, and this has heretofore been impracticalin other mechanisms such" as supporting hubs which were required tosupport the trim strip at the plane of the web, so that the blade couldnot be shifted axially outwardly. Because of improved control, lack offlutter etc., the present support can be below the blade without the webtearing back of the slit,

FIGURES 3 through 5 show the mechanism for supporting and removing thetrim strip T including the trim chute 12.

The trim chute 12 includes a support plate with separate support plateportions. 1

A horizontal plate portion 18 supports the trim strip as it enters thecutting area and the plate portion 18 has a recess 19 formed in one sideto accommodate the slitter band which projects up from the edge of therecess and side of the slitters 10 and 11, the plate curves downwardlyand a plate portion 20 leads downwardly out of the path of travel of theweb W. I

The downwardly curved plate portion 20 and the horizontal plate portion18 have a series of air jet openings 24 in the surface adjacent theinner edge of the trim strip T. These jet openings 24 are provided witha high velocity stream of air so that the air will spread out in acushion below the trim strip and support the strip as it passesdownwardly to the lower open end 27 of the chute. While one row of jetsare shown, with wide trims, a plurality of rows should preferably beprovided. The plurality of rows would be provided by a plurality ofmanifolds each with jets, extending in parallel rows. For example, inwidths of trim over four inches an additional row of jets should beprovided on about two inch centers. The high velocity air upon enteringthe zone below the trim strip spreads out to drop in velocity creatingan area of reduced pressure so that the atmospheric air above the striptends to hold it against the plate portions 18 and 20. This is asignificant feature of the arrangement which is provided. This willcause the strip to closely and accurately follow the curvature of thedownwardly extending surface of the plate portion 20, preventing flutterand preventing loss of control of the strip.

Protection may be provided over the top of the strip such as bycompleting the chute with sides 22 and 23 and a top 21. The chute isprovided with suitable mounting brackets and is supported on the motorframe as above described. In some instances where the slitter band maybe used with a pipe slitter where the band is mounted with other bandson a single shaft, it may be desirable to provide support mechanism forcarrying the chute 12 from another location.

For supplying high velocity air to the jet openings 24, a manifold 25 isprovided beneath the lower surface of the plate portions 18 and 20. Thisis conveniently done by slitting a length of tubing and securing theedges of the slit half of the tubing to the undersurface of the plateportions 18 and 20 with the end of the tubing being closed. At the entryend, the tubing is provided with an air connection fitting 26 forsupplying air. The jets are preferably directed at an angle in thedirection of travel of the trim strip in an angle (FIGURE 3) ofsubstantially 30 with the normal to the web has been found satisfactory.

As previously stated, the upper surface of the plate portion 18 isslightly below the lower edge of the slitter knife with the slitterknife being axially movable over the surface 18.

In operation, the slitter knife 10 and slitter band 11 are set axiallyto provide a trim strip of the desired with relative to the web W, andair is directed to the, manifold 25 to be emitted from the jets 24. Assoon as the web passes through the slitters and the strip is out fromthe edge it will follow down along the surface portions 18 and withoutdanger of gathering or jamming. The strip is uniformly drawn awaywithout flutter reducing the chance of the web tearing ahead of thelocation where it is cut by the slitters. The present arrangement worksfully as well at high speed operations as at low speed, and heretoforespeeds on the order of 2,000 feet per minute have been considered to beas high as practical, but with the present arrangement speeds on theorder of 5,000 feet per minute are accomplished without difficulty.

The air jet openings are preferably inch in diameter and the uppercurvature of the plate portion 20 is preferably swung about an arehaving its center 28 slightly outside of (to the right as shown inFIGURE 3) the center 27 of the lower slitter band, such as on the orderof inch. The surfaces 18 and 20 should be smooth and brightly polishedalthough this is not as critical as with structures heretofore usedinasmuch as the air cushion will positively control and support the trimstrip.

For aiding in holding the web in position, means are provided forremoving air from the surface of the lower slitter band 11 such as by acurved doctor blade 15, FIG- URE 1. This is a significant feature ofoperation since the air on the band 11 is turbulent and its removal isvery advantageous.

. web W. There is considerable volume of turbulent air travelling withthe web which normally causes undesirable.

flutter when the air combines with the turbulent air travelling with theslitter band and/ or the rotating trim support. The leading edge of thearea 18a of the plate portion eliminates this flutter by removing theair from the sheet surface. g i

Thus it will be seen that I have provided an improved trim slitterarrangement which meets the objectives, advantages and features aboveset forth. The unit is well suited for use in trimming the edge of atravelling paper web and is capable of handling webs of substantiallyany Width or weight and may be used with different types of webs. Theweb does not tear ahead of the slitting point and the resistant frictionin the path of the trim has been eliminated.

The drawings and specification present a detailed disclosure of thepreferred embodiments of the invention, and it is to be understood thatthe invention is not limited to the specific forms disclosed, but coversall modification-s, changes and alternative constructions and methodsfalling within the scope of the principles taught by the invention.

I claim as my invention:

' 1. A web slitter for trimming a strip from the edge of a travellingweb comprising in combination,

an upper circular slitter knife,

a lower slitter band coacting with the knife for trimming the outer edgefrom a travelling web,

a trim strip member having a surface outwardly of the slitters extendingout of the path of the web for carrying away the trimmed strip,

means directing a flow of high velocity air into the space between saidsurface and the trimmed strip so that the strip will be controllablyheld and guided along the surface, and

doctor means having a doctoring edge doctoring an air film from thesurface of the slitter band.

2. A web slitter for trimming a strip from the edge of a travelling webcomprising in combination,

first and second slitter members for slitting and trimming an outer edgefrom a travelling web, said slitter members overlapping to form acutting zone,

an arcuate control member having a surface curving away from the slittermembers out of the path of the web,

means defining openings in said surface, and

means for directing a flow of air through said openings between thesurface and the trimmed strip, said flow of air being present at thecutting zone.

3. A web slitter for trimming a strip from the edge of a travelling webcomprising in combination,

an upper circular slitter knife,

a lower slitter band co'acting with the knife for trim ming the outeredge from a travelling web, said slitter members overlapping to form acutting zone,

a trim strip guide member having a surface outwardly of the slittersextending out of the path of the web for carrying away the trimmedstrip, and

a plurality of air jets opening between the strip and the surfacedirected at an angle to said surface in the direction of movement of thestrip, said air jets being present at the cutting zone.

4. A web slitter for trimming a strip from the edge of a travelling webcomprising in combination,

first and second slitter members for setting and trimming an outer edgefrom a travelling web, said slitter members overlapping to form acutting zone,

a guide plate outwardly of the slitter members turning out of the pathof the web with an upper surface facing the trimmed edge strip,

a plurality of jet openings in the surface of said plate,

said openings being present at the cutting zone,

an elongate manifold extending along the back of the plate communicatingwith said openings, and

means delivering air to said manifold to be emitted from the openingsand supportingly hold the strip to follow the surface.

5. A web slitter for trimming a strip from the edge of a travelling webcomprising in combination,

an upper circular axially-movable slitter knife,

a lower circular slitter band,

a direct drive motor for the band,

means receiving the web from the slitters after an edge is trimmedtherefrom,

a rectangular shaped trim chute on the off running side of said slittershaving a lower support surface extending out of the path of the web witha first horizontal portion parallel to the path of the web and a secondcurving portion extending downwardly, said first portion of said supportsurface being below the slitter blade to permit axial movement of theblade over the surface,

a plurality of openings in said surface arranged in a row substantiallyparallel to the path of travel of the web,

a split tube manifold on the under surface of the chute attached theretocommunicating with the openings,

said openings extending for an angle of substantially 30 to a linenormal to the support surface and extending generally in the directionof travel of the trimmed strip, said chute supported on said motor,

means for delivering a flow of high velocity air to said manifold,

a doctor member having a doctoring edge in advance of the on runningside of said knives positioned for removing air from the surface of theslitter band, and

6 a plate attached to said chute extending horizontally beneath the webparallel to the web supporting the web after the strip is trimmedtherefrom. 6. A web slitter for trimming a strip from the edge of 5 atravelling web comprising in combination,

slitter means for slitting and trimming an outer edge from a travellingweb travelling along a first path,

said slitter means forming a cutting zone, said edge travelling along asecond path out o the first path after being slit, and

at least one row of air jets extending along said second path fordirecting a flow of air along the surface of the edge providing aposition controlling air film support therefor, said air jets beingpresent at the cutting zone.

References Cited by the Examiner UNITED STATES PATENTS 548,784 10/1895McCreary 8350l X 2,084,967 6/1937 Babb 83-165 X 2,417,556 3/1947 Kramer83165 X 2,500,772 3/1950 Reed 83165 X 3,127,080 3/1964 Allander et al.226-97 3,143,016 8/1964 Obenshain 83-98 FOREIGN PATENTS 840,930 1/1939France.

OTHER REFERENCES IBM Technical Disclosure Bulletin, v01. 4, No, 10,3-62, page 8.

March 8, 1962.

WILLIAM W. DYER, JR., Primary Examiner.

F. T. YOST, Assistant Examiner.

1. A WEB SLITTER FOR TRIMMING A STRIP FROM EDGE OF A TRAVELLING WEB INCOMBINATION, AN UPPER CIRCULAR SLITTER KNIFE, A LOWER SLITTER BANDCOACTING WITH THE KNIFE FOR TIMMING THE OUTER EDGE FROM A TRAVELLINGWEB, A TRIM STRIP MEMBER HAVING A SURFACE OUTWARDLY OF THE SLITTERSEXTENDING OUT OF THE PATH OF THE WEB FOR CARRYING AWAY THE TRIMMEDSTRIP, MEANS DIRECTING A FLOW OF HIGH VELOCITY AIR INTO THE SPACEBETWEEN SAID SURFACE AND THE TRIMMED STRIP SO THAT THE STRIP WILL BECONTROLLABLY HELD AND GUIDED ALONG THE SURFACE, AND DOCTOR MEANS HAVINGA DOCTORING EDGE DOCTORING AN AIR FLIM FROM THE SURFACE OF THE SLITTERBAND.